


Eat Her

by fallenseraphciel



Category: Kuroshitsuji | Black Butler
Genre: Adult Ciel Phantomhive, Alternate Universe, Blood and Gore, Cannibalism, Dark, Demon Ciel Phantomhive, Demons, Established Relationship, F/M, Fledglings, Human Katherine Pierce, M/M, One Shot, Post-Season/Series 02, Sexual Relationship, Stealth Crossover, Vaginal Sex
Language: English
Status: Completed
Published: 2019-07-28
Updated: 2019-07-28
Packaged: 2020-06-30 10:54:41
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 1,640
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19851676
Author URL: https://archiveofourown.org/users/fallenseraphciel/pseuds/fallenseraphciel
Summary: A fledgling Ciel struggles with his demonic awakening in a primal way.





	Eat Her

**Author's Note:**

> Post Season 2 where Ciel is turned into a demon except he is 18. Sebastian and Ciel have an established sexual relationship.
> 
> WARNING: This has a heterosexual smut scene in it, other triggers tagged above
> 
> This was written for the Demonic Sebaciel Prompts event on tumblr hosted by secretly-a-wuss and chromehoplite

"I know this is a strange experience for you. I know that you aren't used to taking orders from me but, for the time being you must, for your own safety."

Sebastian stood over his fledgling charge who was sitting on the hotel bed. 

"Everything is different. My senses are burning. The aroma of everything is giving me a headache!"

Ciel rubbed his sore temples. Even his own extremities didn't seem the same. His awakening wasn't treating him kindly.

"I understand. Your third eye is opening." He took his hands in his own. "You will also began to feel less inhibition towards your desires. I cannot let you do whatever you wish. It could cause... problems."

"I don't understand?"

"I am talking about the dark desires within your heart. Sex. Violence. Murder. You could swallow souls without ever contracting them, for example."

Ciel's gaze found the floor as he thought. The patterns on the rug only made his head throb more and dizzied him. 

"There are things fledglings must be protected from- reapers, other demons and hunters."

His eyes focused on Sebastian again. 

"Demon hunters?"

"I'll explain more when you're older. I will protect you, as always."

His head swam with all of the new information. He was under the impression that only reapers and other demons could harm him. His butler never spoke of demon hunters but Ciel never asked. 

"There are very few hunters who possess the skill to execute a demon, even a fledgling." He titled Ciel's chin up. "Do not fear anything. You are a thing of hellfire now."

Sebastian's eyes burned red. He kissed him. 

_I didn't want to eat your soul. At first, I did but as we became close I could bear the thought less and less. You are **mine** forever now, beautiful fledgling._

Ciel pulled away. "What?"

"What is it, my lord?"

"You just spoke! Don't play stupid."

"Telepathy," he sighed. "It must be one of your gifts."

Sebastian swallowed hard. 

"At the end of our contract you didn't want to eat my soul?"

"Can you destroy something you've come to love?"

Sebastian kissed him with sincerity. He kissed back with the same intention. Ciel spread his legs and dragged him to the bed with him by his tie. Kissing was definitely enhanced. His fingers clawed at Sebastian's dress shirt. They were lost in each other's lips. After some time, Sebastian pulled away. 

"I have to tend to something at the manor quickly. I will be back shortly. We haven't decided what we are going to do. For now, I'm going to tell them you are still at the Trancy manor."

"Alright."

"Do not move from that spot on the bed. Whatever your mind says, ignore it until I get back."

Ciel didn't reply.

"Understand?"

He nods. 

"Good. Stay."

Sebastian left in a blur.

He is reminded that he would have similar speed and strength now. He picked up a mirror to test. 

_I'm going to shatter this mirror with my fist._

Not only did he break the glass but his hand punched through the backing. The force broke the face from the handle.

"Ach!"

In pain, he dropped the remains. As soon as he brought his hand to his face to inspect the damage, the cut had healed. He brushed the shards off his skin with ease. 

"What the hell?"

He rose from the bed. Testing his speed, he ran across the room in a wink. Invigorated, he ran back and forth multiple times.

Ciel smiled, for the first time in years. 

"This is amazing!" 

It felt like a fireball was bouncing inside the walls of his chest cavity, restless.

_To hell with him. I'm going out._

Roaming the dark streets of London was a new experience for him. It was grimier and more rancid to his refined demonic senses. It was not darker though, his vision cut through the night. Gaslight blurred in the swallow puddles. He heard the distinct sound of heels against cobblestone and turned a few alleyways to find a noblewoman. Alone, she had olive skin, brown curls and eyes to match. Cleavage peaked from above her neckline. She was Ciel's age.

A new pleasure tugged below his gut. 

"Hello."

"Hello," she replied

"And what shall I call the lovely creature before me?"

"Katherine."

"Pleasure to meet you, _Katherine._ "

He tested the sound of her name on his tongue. 

"You're very brave to be alone at this hour."

Fear blossomed in her dark eyes.

"I won't harm you."

His blue eyes burned red and she believed him. That must've been another power. 

Ciel twirled a brunette lock around his digit. The scent of her body was overwhelming in itself but the aroma of her soul was suffocating. It was an entanglement of jasmine, musk and red wine that was almost palpable. 

"You have such glowing olive skin. Are you Italian?"

"Bulgarian."

"Ah."

The fledgling persuaded her against the wall with his steps. His hand rested near her head against the brick. 

"Are you a virgin?" he compelled the truth from her.

"No."

"Do you want me?"

 ~~~~"Yes."

Through the darkness he could see her blush. He could hear her swallow pants, the flutter of heart speeding up and the blood rushing through her body. Their lips met. He attacked Katherine's with his own. Feather-light he grazed her bare shoulder with his finger tips. Then he removed her evening gloves. She shivered. His mouth strayed and traveled down her chin and neck. 

"Ah!"

He devoured the flesh with lips and tongue. Ciel hoisted his hand under her skirt and petticoats. It glided up across her smooth leg. He tore her bloomers down. She moaned. Again, his tongue pressed against her's. His digits slid across her entrance and she was wet. Ciel pushed two fingers in with ease. Katherine squirmed. Pumping them into her, he let out a low, sensual chuckle. 

"Your body is so responsive."

Her breath hitched as a reaction. Lips found her petal soft neck again. He pulled his hand away and she whined at the loss. He undid his jacket and shirt, letting them fall to the damp ground. She reached behind herself, unbuttoning her dress. She stepped out of it and was left in her corset and underskirts. They fell as she untied them. As she went to unclasp her corset, Ciel's hand stopped her. 

"Leave the corset on."

"Okay."

Ciel unbuttoned his pants, leaving it open enough for his member. Katherine smiled at the sight of it. She pushed him onto the ground.

"Greedy girl."

Her hands caressed his face and she kissed him. Then, she slowly sank down onto him. 

"Fuck," he breathed.

She rode his length and her pale blue cameo necklace bounced on her chest. Ciel dug his fingers into the meat of her hips. Katherine let out loud pleased sounds. He thrust up into her.

After an hour, they both climaxed. Her skin was drenched in sweat. Ciel's was dry.

"That was the best sex I've ever had." 

Exhausted, she rested her head on his shoulder.

"I'm starving," he said.

Katherine laughed in agreement

* * *

Tied up longer than expected, Sebastian finally arrived at the hotel. His eyes widened at the discovery of a missing master.

_I shouldn't have left him alone._

Not knowing what trouble Ciel could've gotten into, Sebastian set out to search for him. 

"He can't have gotten far."

Soon, he sensed his master. Then he heard a blood-curdling scream. When he reached the alley, the overwhelming smell of blood and gore hit him. 

Ciel gazed up with wide eyes full of terror. Blood and gore covered his mouth, neck, arms and bare chest. It matched his eyes. The scene before Sebastian would have distributed any sane mind. A heap on the ground was a woman's body. Her neck was torn out. She had a hole in her abdomen through her corset and stomach. Insides spilled out from the corset like a destroyed bouquet of roses. Some of the "flowers" were bitten into. Her dark brown eyes were open wide, lifeless. Dried tears stained her cheeks. 

"Sebastian, I'm sorry." 

Ciel's voice shook.

Sebastian kneeled beside him and pulled him into an embrace. Still in shock, Ciel did not return it.

"It's alright. You're young still. I have to teach you many things."

"She was _so_ _warm_ inside and then everything in my being- Voices in my head! They screamed ' **EAT HER** '."

He smoothed his hair to comfort him.

"Cannibalizing is a primal desire of our kind. However, we don't do it anymore. We only consume their essences, understand?"

He nodded. 

"Such a wonderful soul to go to waste..." he pondered.

Ciel pulled away and their sights connected. 

"You should take her soul. She won't go to Heaven," he continued. 

"I can't."

"Then let's keep it, shall we?"

"Keep it?" 

Sebastian walked to her and laid a hand on her chest, just below her collarbone. From her body a glowing orb was drawn out. He captured it in his hand.

"If you'll recall, Alois' soul was held in a ring. We can find a more suitable vessel for her's, like a necklace. Someday, maybe you'll want to eat it. But I know you want to have it. You were drawn to it."

"Let's keep it then."

"Do you feel better now?"

"Oddly, yes."

Demons do feel differently from humans.

"Never do that again. Eating people is distasteful and disgusting. She was such a beautiful human."

Out of respect, Ciel covered her body with her dress. He shut her lids with care. 

Sebastian whisked Ciel's wet clothes off the ground. Evidence. 

"What will happen to her?"

"The Yard will find her in the morning. Her family will bury and mourn her."

"Draw me a bath."

"Yes, my Lord."

They left the murder scene, Ciel's bloody hand intertwined with his.

**Author's Note:**

> I didn't kill Katherine because I hate her. I actually love Katherine. She just made a wonderful Victorian woman stand-in, even if somewhat OOC. 
> 
> Also sorry he didn't /eat/ her in the other way as well. Sebastian would've. Maybe sometime I'll write Sebastian/Canon Katherine. Hot.
> 
> Proofread this myself only so let me know if there are any errors.


End file.
